A wireless communication system can have an error in transmission data according to channel status of a radio resource carrying the data. Hence, to raise transmission reliability, the wireless communication system controls and corrects the data error using HARQ as shown in FIG. 1.
FIG. 1 depicts a method for transmitting HARQ feedback information in a conventional wireless communication system.
As shown in FIG. 1, when a transmitting end 100 transmits packets to a receiving end 110, the receiving end 110 transmits HARQ feedback information of the received packets to the transmitting end 100 after Transmission Time Interval (x TTIs) 120 pass from the packet reception time. Here, the HARQ feedback information includes ACK indicating reception success information of the packet, NACK indicating reception failure information of the packet, and Discontinuous Transmission (DTX) indicating that the packet reception is not confirmed.
When the transmitting end 100 receives the NACK for a packet 1, the transmitting end 100 retransmits the packet 1 to the receiving end 110 after a retransmission time interval (y TTIs) 122 passes from the NACK reception time.
Using the HARQ scheme as above, the receiving end 110 transmits the HARQ feedback information to the transmitting end 100 for the packets received from the transmitting end 100. In this case, the receiving end needs to activate 130 a transmission power amplifier to transmit the HARQ feedback information though there is no data to transmit through an uplink, and thus power is consumed inefficiently.
Thus, the wireless communication system requires a method for reducing the inefficient power consumption according to the HARQ feedback information transmission in the receiving end.